Diaphragm for duplicators.



No. 867,345. PATBNTBD OUT. 1, 1907. M010: J. D. CARTER.

DIAPHRAGM FOR DUPLIGATORS.

APPLICATION FILED MAR. 10, 1906.

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UNKTE il- STATES PATEN OFFICE.

DIAPHRAGM FOR DUPLICATORS.

Specification of Letters Patent.

Patented Oct. 1, 1907.

Application filed March 10, 1906. Serial No. 305,419.

To all whom't't may concern:

. Be it known that I, MCION JAMEs DOUGLAS CARTER, a subject of the King of Great Britain, and a resident of Hackney, London, England, haveinvented certain new and useful Improvements in Diaphragms for Duplicators, of which the following is a specification.

This invention relates to diaphragms for duplicators the principal object being to keep the cloth or silk diaphragm tight and to be able to take up the slack produced by use. The diaphragms referred to are pieces of cloth or silk used to support and form a backing for the thin stencil sheet. The ink passes from the diaphragm through the stencil sheet to the paper on which the impression is to be taken. The stencil sheet is held on the diaphragm by adhesion.

According to this invention a fabric diaphragm is provided along its edges with bars operatively connected with adjustable tightening devices.

The invention will be fully understood by reference to the accompanying drawings in which 2- Figure 1 shows the duplicator frame with the diaphragm and its connections raised, and Fig. 2 is a section through a portion of the frame showing one of the adjusting screws and the ineans employed for tightening the diaphragm.

Like letters represent like parts in the two figures.

A is a wooden or other frame of suitable proportions; it is hinged or pivoted in any convenient manner as at A to the frame 13 of the bed B which is usually made of slate. Springs C secured to the frame A serve to open the latter when its fastening is released, while extensions A of the hinged member A engage with pins A which serve as stops and so prevent the frame from opening too wide. The frame may be held in its closed position by a hook B and a screw B respectively fixed to the frame of the bed and the frame of the diaphragm.

The frame A has a groove or recess D of appropriate size to receive the tightening bars E of the diaphragm E and allow of their necessary movement therein. The exact shape of the bars E is immaterial but the shape indicated in Fig. I is convenient. There are four of these bars which are carried in four preferably openended pockets E Fig. 2, formed on the edges of the diaphragm, as clearly shown in the drawings.

Passing freely through holes A in the frame A are tightening screws F, adapted to screw into holes formed in the bars E it is easily seen that turning these screws in one direction will draw the bars outward and thereby tighten the diaphragm E, while turning them in the opposite direction will slacken the diaphragm, and if the screws be entirely unscrewed the diaphragm and the bars will be free and collapsed. The screws F are preferably provided with milled heads, but they may have saw-cuts F, or other means by which they can be conveniently turned by the operator. Most of the screws in the drawings are shown passing through complete holes, but if preferred, one or more of the screws may lie in open slots or recesses as indicated, for example, at the bottom of the frame in Fig. 1, whereby the screws and consequently the diaphragm and its bars can be promptly removed at any time without the necessity for entirely unscrewing the screws. The heads of the screws may be sunk into the substance of the frame A, if desired, as indicated at the bottom of Fig. 1, and the screws can pass through holes in the diaphragm pockets either previously prepared or made by forcing the screws through the fabric.

It will easily be understood that with this arrangement not only can the diaphragm be properly stretched in the first instance, but any slackness due to stretching of the fabric in use can be removed and the diaphragm always kept stretched as tightly as may be desired.

What I claim as my invention and desire to secure by Letters Patent is.-

1. In a duplicator the combination with a frame having channels D, of a diaphragm, side bars to the diaphragm and adjusting screws passing through the channels and the bars for the purpose described.

2. The combination in a duplicator of a frame having channels D, a fabric diaphragm having side pockets E separate bars at the edges of the diaphragm resting in the channels in the frame and adjusting screws passing through the frame and operatively connected with the side bars of the diaphragm for the purpose described.

3. In a duplicator, the combination of a frame, a diaphragm having its edges extending into channels formed in the frame, and adjustable means engaging the diaphragm within said channels for maintaining the diaphragm taut.

4. In a duplicator, the combination of a diaphragm, a

frame supporting the diaphragm and having channels formed in its sides and opening through the face against which the diaphragm bears, independent bars arranged in said channels and connected with the edges of the diaphragm, and means for adjusting the bars in said chan-' nels, for the purpose described.

5. In a duplicator, the combination of a bed, a frame having channels D formed in its sides, a fabric diaphragm having pockets formed at its edges, bars in said pockets and lying within the channels in the frame, and adjusting screws passing through said bars and engaging the frame.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

MCIQN JAMES DOUGLAS CARTER.

Witnesses:

HAROLD WADE, HARRY B. BRIDGE. 

